Postnatal stem cells (meaning those present after birth) are unspecialized cells that can renew themselves extensively and develop into more mature cells having specialized functions. Stem cells may be induced under certain physiologic or experimental conditions to become cells with special functions, such as the beating cells of the heart muscle, or the insulin-producing cells of the pancreas. The process by which a stem cell becomes a cell with special functions is known as differentiation. Differentiation can be induced through use of multiple signals that can include chemicals secreted by other cells, physical contact with neighboring cells, and certain molecules in the microenvironment. Thus, stem cells can be treated with specific signals to become specific types of cells having useful functions. These newly differentiated cells can then be used to generate replacements for cells that are lost through normal wear and tear, injury, or disease.
Periodontal (gum) diseases, including gingivitis and periodontitis, are serious infections that, left untreated, can lead to tooth loss. In fact, periodontal diseases are a major cause of tooth loss, and are a substantial public health burden. Periodontal diseases are characterized by destruction of periodontium (supporting tissue for tooth (e.g., the gums)) including PDL, cementum, alveolar bone, and ginigiva. Periodontal disease can affect one tooth or many teeth. Many approaches have been developed for treating periodontal defects, including guided tissue regeneration, the use of growth factors, and the use of enamel matrix proteins, but none of these methods provides a consistently predictable outcome. Accordingly, there remains a need to find new methods to treat periodontal diseases.